High Energy Inner Shell Photoelectron Diffraction in CO_2

Photoelectron diffraction is an effective tool to probe the structures of molecules. The higher the photoelectron kinetic energy is, the higher order the diffraction pattern is disclosed in. Up to date, either the multi-atomic molecule with the photoelectron kinetic energy below 150 eV or the diatomic molecule with 735 eV photoelectron has been experimentally reported. In this study, we measured the diffraction pattern of C 1s and O 1s photoelectrons in CO_2 with 319.7 and 433.5 eV kinetic energies, respectively. The extracted C–O bond lengths are longer than the C–O bond length at the ground state, which is attributed to the asymmetric fragmentation that preferentially occurs at the longer chemical bond side during the zero-energy asymmetric vibration.